1. Field of the Invention
The present invention relates to a mold for foamed plastic molding suitable for molding a foamed plastic article such as to be used for car seat cushions and seat backs in conjunction with skin covers and, more particularly, to such a skin covered foamed plastic molding which utilizes a middle mold between an upper mold and a lower mold.
2. Description of the Background Art
Car seat cushions and seat backs have been made of a pad member covered by a skin cover. The pad member and the skin cover used to be manufactured separately and combined together later, but it has become fashionable to manufacture a skin covered pad member altogether by forming foamed plastic in a skin cover laid over a mold, so that the process of combining at a later time may be omitted.
However, the contemporary car seats tend to have large side support portions with large curving so that it becomes difficult to place the skin cover neatly over the mold. As a consequence, in order to obtain a skin covered pad member of desired shape it is necessary for the skin cover to be pinned down or taped to the mold, which is an additional complication in the manufacturing process.
To cope with such problems, a mold 1 as shown in FIG. 1, comprising a lower mold 2, an upper mold 3, and a middle mold 4 to be placed in between the former two is used frequently. In this mold 1, an upper portion 6 of the lower mold 2 is openable by means of a hinge 5. An edge 8a of a skin cover 8 is pinched between an end of this openable upper portion 6 and an extended portion 7 of the middle mold 4. The upper mold 3 is placed on top of the openable upper portion 6 of the lower mold 2 and of the middle mold 4.
However, in such a conventional mold 1, the middle mold 4 is attached on one side of the lower mold 2, and in addition the upper mold 3 is placed on top of the upper portion 6 of the lower mold 2 as shown in FIG. 1, so that a great amount of pressure is exerted on the lower mold 2, which can lead to a damage or deformation of the lower mold 2.
Also, since the upper portion 6 of the lower mold 2 is attached by the hinge 5, shielding at the hinge 5 cannot be as complete as that between the upper portion 6 of the lower mold 2 and the upper mold 3, so that liquid foamed resin may penetrate into the skin cover 8 as a result of gaseous leakage, and consequently an amount of such penetration becomes uncontrollable.